1. Field of the Invention
The present invention relates to data communication technologies and, more particularly, to a communication control technology for relaying communication packets.
2. Description of the Related Art
Recently, high-speed Internet services and IP (Internet protocol) phone services have become widely available. Associated with this, high-speed transmission of communication packets (hereinafter, simply referred to as packets) like Ethernet packets (“Ethernet” is a registered trademark) and IP packets is called for. This requires increase in the speed of relaying packets in a communication controller such as a Layer 2 switch, a Layer 3 switch, or a router.
A communication controller is provided with a memory (hereinafter, also referred to as “packet buffer”) for storing packet data temporarily. Generally, packet data is of a variable size. However, management of variable-length storage areas in a communication controller will result in complicated processes. To address this, a packet buffer is divided into units of management (hereinafter, referred to as “segment”) of a fixed size. A packet is assigned to one or more segments. A segment is configured to store data derived from a single packet.
[patent document No. 1] JP 2005-130366
As the speed and capacity of communication controllers are increased, the capacity of packet buffers is increased so that the size of data that can be stored in a segment is increased. The inventor has become aware of a problem in that the scheme of configuring a single segment to store data derived from a single packet leaves large unused areas in the segments.